Compounds having biological activity can be identified by screening diverse collections of compounds (i.e., libraries of compounds) produced through synthetic chemical techniques.
The generation of chemical libraries on and off solid resins have proven to be a valuable resource for the pharmaceutical industry in their endeavors to discover new drugs using high throughput screening (HTS) techniques. In creating the libraries, the compounds are ideally synthesized in situ in solution phase or on a solid support. However, relatively simple synthetic methods to produce a diverse collection of such derivatives in situ are often not available.
Such screening methods include methods wherein each member of the library is tagged with a unique identifier tag to facilitate identification of compounds having biological activity or where the library comprises a plurality of compounds synthesized at specific locations on the surface of a solid substrate wherein a receptor is appropriately labeled to identify binding to the compound, e.g., fluorescent or radioactive labels. Correlation of the labeled receptor bound to the substrate with its location on the substrate identifies the binding compound. Using these techniques, the development of efficient high throughput screening has greatly enhanced the pharmaceutical industry's ability to screen large numbers of compounds for biological activity. Central to these methods is the screening of a multiplicity of compounds in the library and the ability to identify the structures of the compounds that have a requisite biological activity.
Pharmaceutical drug discovery relies heavily on studies of structure-activity relationships wherein the structure of “lead compounds” is typically altered to determine the effect of such alteration on activity. Alteration of the structure of the lead compounds permits evaluation of the effect of the structural alteration on activity.
Thus, libraries of compounds derived from a lead compound can be created by including derivatives of the lead compound and repeating the screening procedures. In this manner, compounds with the best biological profile, i.e., those that are most active and which have the most ideal pharmacologic and pharmacokinetic properties, can be identified from the initial lead compound.
Recently, 2-substituted oxazoles were found to be potent as MMP inhibitors (Sheppard, et al, in Bioorg Med Chem Lett 8(22), 3251 (1998)); 2-substituted imidazoles were found to produce local anesthetic effects (Colombo, et al., Rev Farmacol Clin Exp, 4(1), 41-47 (1987); and 2-substituted thiazoles were found to be selective inhibitors of 5-lipoxygenase (Bird, et al., 5th Int Conf Inflamm Res Assoc (Sept 23-27 Whit Haven) Abst 85, 1990).
Synthesis of substituted nitrogen containing heteroaryls using solution phase chemistry has been previously described. Khristich et al., in Khimia Geterotsiklicheskikh Soedineii, 8, 1136-36 (1983) describe the solution phase synthesis of α-(1-methyl-2-benzimidazolyl)benzyl benzoates. Roe et al., in JCS p 2195 (1963) describe the thermal condensation of imidazoles with carbonyl compounds. Papadopolous, in J. Org. Chem., 42 (24) 3925-29, (1977) describes reaction of imidazoles with isocyanates, while Papadopolous et al., in J. Org. Chem., 44(1) 99-104 (1979) describe reactions of azoles with isocyanates. Cleavage of the silicon-carbon bond of 2-trimethylsilyl-1-methylimidazole and 2-trimethylsilyl-1-benzimidazole to yield 2-substituted imidazoles and 2-substituted benzimidazoles is described by Pinkerton, F. H. and Thames, S. F., in J. Heterocycl. Chem. 9(1), 67-72 (1972). Dondoni et al., in J. Org. Chem., 53, 1748-61 (1988) describe the synthesis of (trimethylsilyl)thiazoles which are reacted with carbonyl compounds to prepared highly substituted thiazoles.
In order to develop new pharmaceutical drugs to treat various disease conditions, it would be highly desirable to be able to generate such libraries of substituted azole derivatives and novel intermediate compounds. Thus, there is a need for a facile in situ method for the generation of a multiplicity of substituted azole derivatives and novel intermediate compounds.